Chronic pain often affects the psyche negatively and can lead to depression or anxiety which in turn exacerbates pain. Sometimes an initial injury may cause pain, and the pain persists even after the injury is physically healed. Some people find this to be true in the case of back pain, Fibromyalgia, cancer pain, Reflex Sympathetic Dystrophy (RSD), Sciatica, genital pain, and Migraine Pain. Research has shown that the more traumatic events a person has experienced throughout his or her life, the more likely one is to develop chronic pain. Trauma also includes neglect, as in childhood emotional neglect. People who have experienced trauma, feel higher amounts of pain in response to an injury and that pain is more resistant to medical treatment.
Trauma is "stored" in the structures of the brain involved in emotion, in particular the hippocampus, amygdala, and anterior cingulate cortex. These are the same brain structures involved with pain.
The brain is divided into two sides and connected by the corpus callosum. It has been observed that people with post traumatic stress and/or chronic pain have decreased left brain, and increased right side functioning. The left side regulates focused attention and the right, open attention. More specifically, left side sees the "focused picture": I was injured and experienced a lot of pain. The right side sees the "bigger picture": I was injured and experienced a lot of pain, but now I am healed.
Normally, new, unprocessed information enters the right side of the brain, is transferred to the left side of the brain where it is analyzed, and then returned to the right side. Extreme affect in the form of high anxiety while experiencing a traumatic event, for example, disrupts this normal information processing. Pain "gets stuck" in the brain, most likely the left side. The left brain may be focused on, "I am injured and still experiencing pain." Even though the physical injury is no longer present, one may experience chronic pain.
The good news: Neuroplasticity. This means that the brain's structure, including how it responds to pain, is changeable by experience. Part of this experience to change the neurons in the brain can take place in during therapy for trauma.
More good news: EMDR. A therapist may use Eye Movement Desensitization and Reprocessing to simulate REM (Rapid Eye Movement), that is the side to side movement of the eyes during sleep, when processing occurs. This stimulates bilateral or left and right side brain stimulation, to help move the "stuck" trauma and pain stored information and process it. This may lessen severity and sensitivity to chronic pain for people who have experienced trauma or neglect in their life. EMDR is a highly researched technique for treating trauma and pain that may be maintained by trauma stored incorrectly in the brain.
Learn more about EMDR for trauma and Post Traumatic Stress (PTSD).